1. Field of the Invention
The present invention relates to a stage apparatus that moves precisely in one dimension or two dimensions over a flat table onto which is placed a mask or substrate onto which a pattern is described, and to an exposure apparatus or the like using such a stage apparatus.
2. Description of Related Art
In the past, in a microlithography apparatus in which a circuit pattern of a semiconductor device or a liquid-crystal device is formed by shining illumination light (an energy beam such as an ultraviolet beam, an X-ray beam, or an electron beam or the like) onto a mask or the like on which a circuit pattern is described so as to perform exposure of a sensitized substrate (a semiconductor wafer or glass plate or the like onto which a resist layer has been applied) by projection through a projection image forming system that is full-size or that has a reduction or magnification ratio, a stage apparatus is provided, onto which the mask or sensitized substrate is placed, and which moves in one dimension or in two dimensions within a plane (XY plane), under position servocontrol by a laser interferometer.
In such a stage apparatus, the mask or substrate is generally vacuum chucked by a vacuum chucking force. In particular, because the surface area that is held by the vacuum chucking is small and scanning is done at a speed that is approximately 4 or 5 times that of the wafer, there is a tendency for the mask holding force to be insufficient, so that the mask position shifts during the scanning of the mask stage. For this reason, there is a technology, as shown in Japanese Unexamined Patent Application, First Publication No. H10-149979, of pressing a member serving as a positioning reference up against the mask, so as to prevent offset.
In recent years, in order to improve the productivity of exposure apparatuses, there is a desire to increase the speed of the reticle stage apparatus or wafer stage, so that the acceleration to which the wafer is subjected reaches 5 to 6 G.
In the above-described technology, however, because the force that holds the mask is only the vacuum chucking force that acts on the bottom surface of the mask, if the stage apparatus is moved with a high acceleration, there is the problem of insufficient holding force, resulting in mask offset and a deterioration of the transfer precision.